This invention is directed to a method of optimizing spacing between elastic members, thereby optimizing gasketing pressure distribution, in the application of leg elastics to a garment. The method involves adjusting pivot arm alignment and elastic guide location.
Pant-like absorbent garments, such as diapers and training pants, typically include a pair of leg openings having an elastic portion around each leg opening. The elastic portions are intended to fit snugly around a wearer""s legs to prevent leakage from the garment. However, more gasketing pressure is required in certain areas around the leg, such as in the crotch area, than in other areas around the leg, such as in the dwell areas away from the crotch.
Various technologies are known for applying leg elastics to such articles. For example, some technologies involve increasing spacing between elastic members at the crotch area around each leg opening. This type of spacing results in low gasketing pressure in the crotch area and higher gasketing pressure in the areas away from the crotch. This type of spacing is the normal process fallout due to the correspondence between the angle of application and the spacing between the elastic members.
More particularly, when the elastic members are applied to a garment in a machine direction, variations in the angle of application result in variations in spacing. When a device used to apply the elastic members aligns the elastic members in the crotch area in a row substantially perpendicular to the machine direction, as the elastic members are guided away from the crotch area, the angle between the row and the machine direction is closer to 0xc2x0, thereby resulting in wider spacing in the crotch area and narrower spacing in the area away from the crotch. Other technologies boast consistent spacing between elastic members around the entire leg opening. Some of the technologies mentioned, and others, include consistent gasketing pressure around the entire leg opening.
There is a need or desire for a process for optimizing spacing among elastic members around the leg openings of pant-like absorbent garments to provide enhanced comfort, fit and containment about the leg openings of such garments.
It has been found that variations in spacing among elastic members, other than the normal process fallout, are factors that can be optimized to provide enhanced comfort, fit and containment about the leg openings.
The present invention is directed to a method of applying leg elastics to pant-like absorbent garments using variable spacing among the elastic members. More specifically, gasketing pressure distribution around a wearer""s legs is optimized by changing the spacing between the elastic members, and curving the leg elastics at the same time to optimize the performance of the leg elastics for enhanced comfort, fit and containment.
In one embodiment of the invention, a pivot arm parallel to a substrate as the substrate is fed through a pair of nip rolls is used to carry out the method of the invention. Furthermore, the pivot arm includes elastic guides spaced at different radii from a pivot point on the pivot arm. This invention can provide customized higher gasketing pressure anywhere in the leg area for higher gasketing, and lower gasketing pressure over any area in the leg area for better comfort. These areas can be customized in any shape on the product which would offer an ideal fit all the way around the leg. For example, a resulting absorbent garment can have narrow spacing over a back part of the leg, medium spacing in the crotch area, and wide spacing over a front part of the leg away from the crotch area.
In another embodiment of the invention, a pivot arm which is perpendicular to a substrate as the substrate is fed through a pair of nip rolls is used to carry out the method of the invention. In this embodiment, the pivot arm also includes elastic guides spaced at different radii from a pivot point on the pivot arm. A resulting absorbent garment can have narrow spacing in the crotch area and wide spacing in the area away from the crotch.
In yet another embodiment of the invention, a linear arm which is perpendicular to a substrate as the substrate is fed through a pair of nip rolls, with elastic guides on a rotating pivot guide on the arm, is used to carry out the method of the invention. In this case, a resulting absorbent garment can also have narrow spacing in the crotch area and wide spacing in the area away from the crotch.
With the foregoing in mind, it is a feature and advantage of the invention to provide a method of applying leg elastics to an absorbent garment resulting in optimized performance of the leg elastics in terms of comfort, fit and containment.
It is another feature and advantage of the invention to provide a method of tailoring leg elastic spacing in an absorbent garment to optimize gasketing pressure to fit a wearer""s body.